Start the base by cooking the leek and Alexanders in butter for 5 minutes on a medium heat in an oven-proof pan. Add the minced beef and brown for 10 minutes, stirring constantly. Cut the carrot into 6-8 chunks, add to the beef together with the chopped mallow and pour in the vegetable stock. Let everything simmer for 20 minutes. Take the carrots out, checking that they are soft, and put them in a blender to make a carrot mash, adding salt and pepper. Top the beef with the carrot mash and grill for 10 minutes (or less, depending on your grill) to create a crunchy topping.